<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="../vue.js"></script>
    <style>
        .aa{
            background: red;
        }
        .bb{
            font-size: 100px;
        }
        .cc{
            font-family: "Arial Narrow",fantasy;
        }

    </style>
</head>
<body>
<div id="box">
    <div :class="classObj">hello </div>
    <div :class="classArr">world </div>
</div>
</body>
<script>
    var obj = {
        data() {
            return {
                classObj:{
                    aa:true,
                    bb:true,
                    cc:true
                },
                classArr:[]
            }
        },

    }
    var app = Vue.createApp(obj).mount("#box")
</script>
</html>